In the present day, ion implanters are often constructed to optimize implantation according to a specific set of applications. In current applications, for example, some beamline ion implanters are configured to generate high current ribbon beams in which the beam cross section that intercepts a substrate is defined by a beam width that is much greater than the beam height.
In the present day it is common to perform ion implantation using ribbon beams in an ion implanter that is dedicated to ribbon beam implantation, where a ribbon beam is directed to the substrate having a beam width sufficient to cover an entire substrate along a first direction of the substrate. The ribbon beam may have a much smaller height than width, where the ribbon beam height along a second direction perpendicular to the first direction is smaller than a substrate dimension along the second direction. In this manner, just a portion of a circular or rectangular substrate is exposed to the ribbon beam at one instance. Consequently, the entire substrate may be exposed to the ribbon beam by scanning the substrate with respect to the ribbon beam along the second direction.
However, if the ribbon beam exhibits non-uniformities in current density, for example, these non-uniformities may be reflected in non-uniform dose that is received by the substrate. For example, small fluctuation in current density may occur locally within portions of a ribbon beam during an ion implantation process, which may result in areas of higher or lower implant dose within a substrate that is exposed to the ribbon beam. It is with respect to these and other considerations that the present improvements have been needed.